<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>css盒子模型</title>
    <style>
        div {
            width: 200px;
            height: 200px;
            /* 简写 */
            /* border: 2px solid pink; */
            /* 方法二 */
            /* 上边框 */
            /* border-top: 5px dashed red;
            /* 下边框 */
            /* border-bottom: 4px dotted lightblue;
            /* 左边框 */
            /* border-left: 4px dotted lightblue;
            /*右边框  */
            /* border-right: 4px dotted lightblue; */

            /* 方法一：包含四个边框 */
            border: 4px solid red;
            /* 层叠性（就近原则）：只层叠了上边框 */
            border-top: 4px solid lightblue;
        }
    </style>
</head>

<body>
    <div></div>
</body>

</html>